Problems arise during meditation because of the modification of the mind. A modification of the mind is any instance where a mental impression, such as a thought or an image, arises in your mind, thereby altering from its empty, pure, and serene natural state.

I don’t want to propose that all thoughts and images in the mind are necessarily bad. And I certainly don’t want you to judge yourself anytime a thought or an image arises. You don’t want to suppress or repress anything.

Nevertheless, the purpose of meditation, obviously, is to quiet the mind. And you can achieve this by becoming more aware of the thoughts and images and by resisting the urge to identify with them.

Whenever thoughts and images do arise, there is a corresponding reason. That's why I want to outline the five primary modifications, the five types of “mind chatter” or “monkey mind:"

There are three means by which a person can attain correct knowledge. One, through direct perception, or gaining evidence of through the senses, such as seeing. Two, through inference, or through arriving at knowledge by a logical conclusion. And three, through testimony, or through the word of an acceptable, reliable, and trustworthy authority.

Wrong knowledge is knowledge determined as such after study. Wrong knowledge could range anywhere from inaccurate scientific theory and faulty medical diagnosis to wrong testimony in a court of law. As such, wrong knowledge is the basis for the majority of suffering in human life.

3. Imagination

Imagination is the process of looking into the future and forming a mental image or concept of something that one could experience.

4. Memory

Memory is the process of looking into the past and holding the impression of things one already experienced.

5. Sleep

You may be wondering why sleep is listed as a modification of the mind, when the deep sleep state especially is an absence of all thoughts and images whatsoever.

Well, deep sleep is listed as a modification because the deep sleep that most people experience is unconscious. When you fall asleep and descend into the deep sleep state, you lose all awareness.

It’s possible to descend into deep sleep consciously, but this requires a practice of yoga nidra, or yogic sleep, which is similar to meditation. View my article on those here.